Clock



FIG. 1 is a perspective view of a clock, showing the new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a right side elevation shown with the clock in an alternate position, the left side view is a mirror image thereto.

The broken lines shown in FIGS. 1 and 2 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a clock, as shown and described. 